Motor-controller.



GIE. EEEDEEEONK MOTOR CONTROLLERJ APPLICATION EILED APE.23,1909.

Patented'May .27, 1913.

Y xw\ UNITED srArEs CLARK T. HENDERSON, F MILWAUKEE PATENT -oEEroEWISCONSIN, Assrenon 'ro TEE oUrLEn- HAMMER MFG. CO., OF MILWAUKEEWISCONSIN, A CORPORATION OF 'WISCONSIN'.

MOTOR-CQNTROLLER.

Application led April 23,

To all whom t may concern.'

Be it known that I, CLARK T. HENDERSON, a citizen of the United States,residing at Milwaukee, in the county of Milwaukee and State ofWisconsin, have'invented new and useful Improvements inMotor-Controllers, of which the following is a full, clear, concise, andexact description, reference being had to the accompanying drawing,'forming a part of this specification.

My invention relates to improvements 1n controllers for electric motors.

there is an excessive lMore particularly it rela-tes to controllers inwhich a plurality of lautomatic switches are provided for acceleratingthe motor, and

in which each' of the accelerating switches is provided with anautomaticrelay device for preventing .theoperation thereof, while flowof current through the ino-tor.

According to my present invention, I arrange the relay devices in such amanner that they will all respond immediately upon closure of the motorcircuit to render all of ythe accelerating switchesinoperative, and

to thereafter operate successively as the flow of current through themotor decreases to cause successive operation of the acceleratingswitches.

lIn order to more fully'disclose the characteristic features of myinvention, I shall describe" the controller diagrammatically illustratedin the` accompanying ldrawing which embodies my invention in itspreferred form. Of course,I my invention is susceptible of variousmodifications.

The controller illustrated includes a;

main line switch l, resistance switches 2,"

' 3 and 4. 'and relay switches 5,v 6 and 7.

AThe mar'switch l has an operating wind-' ,ing la. l carries a contactvThe plunger of the winding4 la disk 8 adapted, when the main switch lis closed, to bridge a pair of stationary contacts. The purpose o'f thisContact disk lwill he 'hereinafter setA forth.l The resistance switches;2, 3 and '4l are provided with operating windings 2,-

3. and 4a, and are adapted to control ref sistance sections R2, R8 vandR"-respx-ictivel'y.'`

The resistance's just mentioned are arranged in series with the motor,which,` as illustrated, is provided with an mature and a series fieldwinding F. Eachofthe' relay switches 5, 6 and 7 1s connected in ou?,

emit-with,y theA 'operating vwi-ruling y ci' Aone of Specification ofLetters Patent.

the resistance switches. ,The -relay switches 5, 6A and 7 are providedlwith operating windings 5, 6a and 7a respectively, each of whichwinding is adapted to operate its corresponding relay switch to open thecircuit of one of the resistance switches. As will be hereinafter moreclearly ,set'forth, the operating windings of the relay switches are allconnected in series with the motor,where by when the motor circuit isclosed,` current will flo-w through'all of saidwindings. order that theoperation of this controller may be more clearly understood, let it beassumed that a current of say 3.00 amperes, flowing through the windingsof the relay 'es In switches, will cause all of 'said .windings "to torcircuit decreases. For instance, winding 5a may be adjusted to releasethe switch' 5. when the current through the motor i's decreased to 250amperes; winding 6a to releasethe switch 6`upon a further drop of 25-amperes; and winding 7 toprelease the switch 7 v upon a still furtherydrop of 25 amperes.

controller.

Current .is supplied from gnain lines 10 Vand 11 through amain lineswitch 12and thev circuit of the operatingn winding la of the mainswitch, is initially controlledfby switchlg.. Upon closure oflswitch'll, current lwill flowixfrom main line i0 by conductors 14; and'l5 through switch 13, by con ductor 16 lthrough' 'the operating winding.1, by rconductors 17, i8 and 19 to the' negativel linell'oftheniifiaiiycircuit. This completes -thegoircuitthroughthe-"winding l, .which thereupon 'becomes energized and closesthe switch V1.; Closure of the switch Incompletes the motor circuitvfrom conductor l5 by conductors 20 and'Ql, 'through ductor 22,' throughthe winding 6a by conductor 28, through the winding 5a by conductor 24,through main line ,switch 1 by conductor 25, through the resistancesections R2, R3 and R4; thence by v conductor 26 through the seriesield'windingj F and ar matureA y'te''concluetor:3;9.. It will thus be Ishall now 'describe' the' operation of the the'winding' 7a ofthe relayswitch 7 by con- :een that the motor is started'with all of the startingresistance in circuit, and that. if theu ductor 28 to conductor 1 6. Theoperatingv winding of each ofthe resistance switches is connected toconductor 28, and hence cur- VArent would iiow through these operatingwindings as soon as the main switch was closed, but for the fact that inthe meantime 'their circuits have been opened at other points by theirrespect-ive relay switches. Consequently, none of the resistanceswitches will close until their respective relay switches have returnedto initial posic tion. It is well understood that upon initial closureof the 'motor circuit there is a heavy rush oi current through themotor, due to the fact that when the motor armature is atrest, there islittle or no drop in potential across yits terminals. It is alsounderstood that as the motor armature increases in speed, it generatesfagradually increasing C. E. M. F., which, in turn, gradually reduces theHow of current'in the motor circuit. Hence, ata certain stagein thestarting period, the motor will generate a sutilcient C. E. M. F toreduce the flow of current through the motor circuit from 300 to 250amperes. When the current through the motor circuit is reduced to thisvalue, the winding 5a will permit the relay switch 5 to return toinitial position.\ The return of the relay switch 5 to initial positioncompletes the circuit of the operating winding 2ll ci the resistanceswitch 2. lThe circuit of this winding may then be traced from conductor28 through the winding 2a, by conductor 3() through' the switch 5, toconductor 18, and thence to the negative line. The windingi2a thereuponbecomes energized and closes the switch 2. The pivotal point of. switch2 being connected to conductor 23, it will be seen that upon closure ofsaid switch, the resistance R2 will be shortcircuited from the motor`circuit, the currentthenv flowing from conductor 23 through the switch 2by conductor 31 through the resista-ncef sections be understood that,the lHow of current through the motor, will immediately increase abcve25@ amperes, and will their. gradually decrease as thearmature increasesvin speed and generates an increased C. E. M. F. After a certaininterval, the current in the vmotor circuit will decrease `to 225.amperea whereupon the winding 6a will permit the rea-y switch 6 toreturn yto initial position. Closure of the relay switch 6 completes thecircuit of the winding 3 of the resistance switch 3. The circuit of thiswinding may then be tracedfrom conductor 28 through said winding vbyconductor 32 through the switch' 6, and thence to conductor 18.Energization of the winding 3a will cause the closure of resistanceswitch 3.. It will be seen, however, that the circuit of the operatingwinding of this resistance switch will not be completed until thecurrent through the motor has decreasedto a safe value. Upon closure ofthe switch 3, the motor circuit extends from conductor 22 through theswitch 3 by conductor '33 through the resistance R4, and conductor 26through the motor. This shortcircuits the resistance R3, and alsoshortcircuits the operating` winding 6a of the relay switch. Removal ofthe resistance R3 v,trom the motor circuit temporarily causes anotherincreased surge of current through the motor. But in a short period theC. E. vM. F. of the motor armature increases suiiciently to reduce theflow of current to 200 amperes. Thereupon the wind- -ing 7"L drops itsplunger, thereby causing the relay switch 7 to complete the circuit of;the operating winding of the resistance switch 4. The circuit of thiswinding may be traced from conductor 2S through said'winding byconductor 34 through the switch 7 to conductor 18.' pletes the motorcircuit from conductor 20 through 'switch 4, thence directlyv throughthe motorto conductor 19. Upon the removal of all of the startingresistance, the motor will quickly come up to normal speed.

Vith the arrangementillustrated, it will be seen that. the relay devicesoperate successively to cause successive operation of the resistanceswitches. But the relay vswitches operate to accomplish this result insuch 'a manner that the motor is always protected against an excessiverush of current therethrough.

Havingthus described my invention,what I claim as new and desire tosecure by Letters Patent, is:

1. In a controller for electric motors, in

Closure. of the switch 4l com- Y combination, a plurality of automaticrcand automatic meansl 'sistance switches, a

` closure of the motor circuit to temporarily prevent operation of saidswitches for vary ing periods.

3. In acont'roller for electric motors, i combination, a plurality ofvautomatic resistance switches and vautomatic means adapted to operateimmediately upon closure of the motor 'circuit to render said switchesinoperative and to thereafter cause said switches to operatesuccessively as predetermined electrical conditions are established.

4. In a controller Vfor electric motors, in combination, a plralit 'ofautomatic resistance switches an electroresponsive means adaptedtorespond immediately upon closure of the. motor circuit to render saidswitches temporarily inoperative and to thereafter cause said switchesto operate successively as redetermined electrical conditions are estalished.

5. In a controller for electric motors, in combination, a pluralityofautomatic resistance switches and a lurali'ty of electroresponsivedevices, one or controlling each of said switches,l all of said devicesbeing adapted to respond upony closure of the,

motor circuit and to thereafter cause successive operation lof saidswitches as prede` electrical conditions are estab-v termined lished. Y

6. In a controller for electric motors, in combination, a 4plurality ofautomatic resistance switches, a plurality of automatic devices, one forcontrolling each'of said switches, said devices heilig arranged torender all of said switches inoperative upon the closure of the motorcircuit and to thereafter cause the same to operate successively aspredetermined electrical conditions are established, each of saidresistance switches upon closing insuring against further operation ofits corresponding controlling device.

7. In a controller for electric motors, iin combination, a plurality ofautomatic relurality of electroresponsive devices, one or controllingeach of said switches, said devices being adapted to respond, upontheclosure of the motor circuit` to render said switches inoperative andto thereafter successively return to initial position as predeterminedelectrical conditions are established, to cause-the operation of theirrespective resistance switches.

8. In a controller for electric motors, in

Copies ot this patent may be obtained for combinatioina plurality ofautomatic' resistance switches, a plurality or electroresaid switches,said devices being adapted to respond, upon the closure of the motor'circuit, to render said switches inoperative, and to thereaftersuccessively return to initial position as predetermined yelectricalconditions are established, to cause the operation 'of their respectiveresistance switches, the

,sponsive devices, one for controlling each of switches as the iiowl ofcurrent through the l motor decreases.

10. In a controller for electric motors, in

combination, a plurality of clectromagnetif troresponsive controllingswitch arranged in circuit with the operating winding of each of saidresistance switches, the operating windings of said controlling switchesbeing connected in the motorjcircuit to operate said controllingSwitches upon closure of the motor circuit',"said Vcontrolling' switchesbe,

ingarranged to successively return to initial position to cause theenergization of, the

windings oftheir corresponding resistance' switches as the iiowjofcurrent through the motor decreases, and circuit lconnections wherebythe'winding of each of said controlling switches is shortcircuited'uponthe closure of its corresponding resistance switch. i

In witness whereo'iI have hereunto sub scribed my name in the presenceof two witnesses. y

- CLARK T. HENDERSON.

Witnesses:

FRANK H. HUBBARD,

S. W. Firz GERALD.

've cents each, by addressing the Commissioner of Patentx Washington, D.C.

sa f 'cally operated resistance switches, an elecioo

